1. Field of the Invention
The present invention relates to rotary regenerative heat exchangers wherein transfer of heat from a heating fluid to a cooling fluid is accomplished by means of heat-absorbent elements alternately exposed to the heating and cooling fluids. More particularly, the invention relates to a rotor construction featuring a rotor shaft and a series of radial plates disposed about the rotor shaft and attached to radial plate pins which help to accommodate system stresses associated with rotary regenerative heat exchanger operation.
2. Description of Prior Art
A common means of attaching the rotor structure to the central rotor shaft has been by welding. A disadvantage of use of such a welded connection is that thermal and bending stresses encountered during operation may result in failure of the weld.
Various rotor configurations for rotary regenerative air heaters have been developed in order to overcome the consequences of these stresses. For example, U.S. Pat. Nos. 3,155,152 (Conde), 3,710,850 (Kurschner et al) and 3,998,266 (Finnemore) are directed at means of reducing such effects through the use of tangential plates, universal-type joints, and ball-and-socket arrangements respectively.
U.S. Pat. No. 3,192,999 (Stockman) shows a support arrangement involving telescopic means to carry an upper rotor section through a lower bearing and a lower rotor section through an upper bearing so that the upper and lower rotor sections expand toward each other during operation.
U.S. Pat. No. 3,891,029 (Mahoney) discloses an arrangement featuring a double pin connection between each heating basket and the rotor shaft, and utilizing U-shaped rotor post brackets and tension and compression fittings to which the two pins are interconnected.
These and similar arrangements are complex in terms of fabrication and field assembly; some are limited to applications in horizontal-axis rotors. In addition, modular rotor construction wherein the heat transfer element units form an integral part of the rotor structure, i.e. are affixed to the shaft by a pinned connection, as shown in U.S. Pat. No. 3,710,850 (Kurschner et al) will allow only axial and possibly some radial movement.